Methotrexate is not associated with an increased risk of lung disease in patients taking it for psoriatic arthritis, psoriasis, or inflammatory bowel disease, according to a meta-analysis.

The prevalence of methotrexate related interstitial lung disease remains unknown but has been reported to be as high as 11.6% in rheumatoid arthritis, the authors from Galway in Ireland wrote in the BMJ.

However their analysis of seven studies and 1,640 participants, showed no increased risk of total adverse respiratory events – infectious or noninfectious – or pulmonary deaths in patients taking methotrexate, compared with controls.

“These findings, coupled with those of a previous study in rheumatoid arthritis, suggest that methotrexate-related lung disease is rare, if it exists at all,” the study authors wrote.

But as their study had several limitations — such as a lack of generalisability — they could not rule out “a rare but important” increase in pulmonary adverse events.